Abell 21 (PK 205+14.1), Gem. February 3, 2021. Beaver Meadow [500 m a.s.l.]. 20" F/5. Clear, transp. 8/10, seeing > 4 arcsec, SQM 20.7 (snow). Not visible in 26 mm without a filter. Obvious with OIII. Crescent-shaped; extended overall NE-SW with enhanced ends, convex to the E. A star is embedded in the N part. A filament separates on the E side, running S to a star. In 13 mm with OIII, the SW end appears separated and has two extensions, to the W and E. [The nebula is fairly prominent in Panstarrs g; the structure corresponds to the one seen visually.]